SITE-INVESTIGATION AND GEOTECHNICAL DESIGN OF D-RUNWAY CONSTRUCTION IN TOKYO HANEDA AIRPORT

Tokyo International Airport (Haneda Airport) is a domestic hub-airport in Japan; however, the increasing number of passengers has brought it close to its capacity. In addition, there has been strong demand for the development of an international-flight network. Consequently, a new runway, called the D-runway, was planned and constructed from March 2007 to October 2010. Because some of the D-runway runs through a river mouth, a hybrid structure consisting of piled pier and reclamation fill was adopted. To overcome the geotechnical difficulties in constructing this hybrid structure on the soft clay deposit, various technologies in design and construction were adopted. This paper provides an outline of the project, the ground investigation, and the design of the D-runway structure from a geotechnical engineering view point. From the results of the site investigation, the stratigraphic model at the site was clarified. For the clay layers, a representative depth-profile for each soil parameter was determined. Some local soil properties which tended to be overlooked when only employing an engineering point of view can be appropriately captured by linking the geological and geotechnical information. In the construction of the D-runway, not only the ground improvement technologies (SD, SCP, and CDM) but also the new developed construction materials (the pneumatic mixing of cement treated soil and air-foam treated lightweight soil) were utilized. In the-D-runway project, various technologies used in previous airport constructions were brought together and applied to the ground investigation, design, construction work, and even maintenance. The construction of the D-runway was completed safely, rapidly, and economically, and it came into use on 21 October 2010, on schedule.